You might have to do this via AGL chat or phone, don't think they will just do this from a forum request, one with a different name and forum username.
And while contacting them to update address details, why not just get your bills sent via email ? (if not already signed up)
I think you should be able to do this by accessing your AGL online account . . . yes, just checked in your profile account settings you can select e-billing.